apply_crdt_state force-sets accumulated scores outside apply_event_local,
so it bypassed the single note_write() chokepoint that keeps the trending
top-K cache fresh. A node going quiescent right after a partition heal kept
serving the pre-reconciliation candidate set indefinitely. Invalidate the
cache in apply_crdt_state too, with a regression test that reconciles a new
high-score entity and requires it in the next candidate read.
Also: extract the for_you/related ANN candidate cap to a named constant
(ANN_PROFILE_CANDIDATE_LIMIT), keep the recall test's ef_search in lockstep
with its construction default (honored since m12p3), and clarify the
vector_search region doc (always null until m12p4 cross-shard reads).
da5d2d4d53